The temperature dependences of kinematic viscosity of liquid stainless steels 10Х23Н18 and 20Х23Н18 have been studied. The existence of critical temperatures, heating above which is accompanied by irreversible changes in the structural state of the melt has been established. A model of the structure of liquid stainless steels has been proposed. The temperature-time regimes of stainless steels melting, providing the raw materials economy and improving the quality of metal products, have been developed.